Inspire yourself of Symfony2 to create better code

Symfony2 is now released and, as the first version of symfony, it's a framework that advocates a lot of best practices. Any developer who works on a Symfony2 application should follow the same rules, in order to keep the project on the right tracks. With the help of Symfony2's code and my personal experience, I will try in this session to bend your mind to some principles like Separation of Concerns and pragmatism, in order to achieve successful projects.

Transcript

1. Inspire yourself by Symfony2 to create better code Marc Weistroff – SensioLabs
2. Have you seen this guy? Marc Weistroff @futurecat
3. h"p://www.flickr.com/photos/joeshlabotnik/4857173373/  
4. How many of you already used Symfony2?
5. How many of you looked at the code?
6. How many of you contributed?
7. WHY SYMFONY CAN BE CONSIDERED GOOD CODE?
8. Because fabpot wrote it !
9. and also more than 300 other developers.
10. Built on powerful concepts •  Separation of concerns •  Pragmatism •  Best practices
11. SEPARATION OF CONCERNS
12. “In computer science, separation of concerns (SoC) is the process of separating a computer program into distinct features that overlap in functionality as little as possible.” -- Wikipedia
13. “A concern is any piece of interest or focus in a program. Typically, concerns are synonymous with features or behaviors.” -- Wikipedia
14. HUH?!
15. Examples of SoC HTML / CSS –  Separating content from styling Internet Protocol Stack – HTTP or SMTP doesn’t care about TCP, nor IP Place where you eat / place where you shit – Don’t mix it up, it’s dirty and can be hazardous
16. Controller View Model The Controller analyses the user request, calls the Model and passes data to the View. The View layer formats data in a dedicated format (html, json…) The Model stores the business logic and classes that manipulate data. Request MVC Pattern
17. Uncoupled components
18. With optional dependencies
19. Bridges •  Bridges couple third party libraries with Symfony components. •  External to the component and the 3rd party library •  Prevent hard-coupling between component and third-party library.
20. HttpFoundation •  Implements the HTTP RFC •  Dedicated objects for – Request – Response / RedirectResponse – Session – SessionStorage – HeaderBag – ResponseHeaderBag
21. Lessons learned
22. Couple your code as less as possible
23. Dedicated object/library for dedicated work/concern
24. THiNK!
25. Is it the job of this class to do that?
26. Does it make sense ?
27. PRAGMATISM
29. Complete list of tips available online http://pragprog.com/the-pragmatic-programmer/extracts/tips
30. Pragmatic approach •  Simple & effective •  Download the project and start immediatly •  Oriented toward the real world, not purity for the sake of purity.
31. Pragmatic approach •  No magic = No WTF effect •  No magic = Keeping control •  Almost always explicit
32. Pragmatic approach •  Code generation thanks to the CLI commands
33. Pragmatic approach •  Easy debugging thanks to WDT •  Meaningful error messages •  Gentle to the end-user
34. Pragmatic approach for your project •  Make a prototype that works, and improve it step by step. •  Refactor early, refactor often. •  THINK constantly about what you’re doing and why you’re doing it
35. Premature optimization abstraction is the root of all evil
36. Coding standards •  Symfony come with it’s own coding standards •  Coming from another framework ? – It can be weird at first time, but you’ll get used to it really quickly
37. Stick to Symfony’s coding standards
38. Design by contract 4 137 0   20   40   60   80   100   120   140   160   symfony  1.4   Symfony2   Interfaces  
39. Contract •  Rights & Responsibilities of an object •  Interfaces are the contracts of OOP •  No surprises •  You can replace an interfaced object with your own implementation, without breaking anything
40. Make interfaces or forever hold your peace
41. Tests •  Symfony2 is heavily tested •  PHPUnit •  ~ 5000 tests, 13000 assertions •  Code coverage – Components : 84% – Bundles: 58% – Bridges: 56%
42. Avoid sleepless nights at work: write tests
43. The wheel, not reinvented •  Rock solid HTTP implementation •  Edge Side Include (ESI) •  HTTP Cache, no applicative cache – Did not reinvent the wheel !
44. If a standardized solution exists: use it
45. BEST PRACTICES
46. Follows PSR-0 •  PHP Standards Working Group •  http://groups.google.com/group/php- standards?pli=1 – autoloader interoperability – Namespace convention
47. No singleton and DIC •  Uses DIC •  No singleton = better testability thanks to the absence of hard-coupling •  Lazy loading •  Reentrancy
48. Interfaced exceptions •  Not present in all components – DependencyInjection, Routing, Serializer, Yaml •  Keeps semantic of the 13 SPL’s exceptions •  Makes it easier to catch exception of a component/library
49. // src/Symfony/Component/Yaml/Exception/ExceptionInterface.php! namespace Symfony\Component\Yaml\Exception;! ! interface ExceptionInterface! {! }! ! ! ! // src/Symfony/Component/Yaml/Exception/DumpException.php! namespace Symfony\Component\Yaml\Exception;! ! class DumpException extends \RuntimeException implements ExceptionInterface! {! }
50. OpenSource cross polination •  Benefit from the work of hundreds of people •  Security Component comes from Spring (Java) •  Monolog was inspired by logbook (python)
51. OpenSource cross polination •  Assetic is based on webassets (python) •  Composer is a port of the SAT solver algorithm of openSUSE’s libzypp (c) •  PHPCR, port of JCR
52. Search for solutions in other languages and port them!
53. and… IT WORKS ! •  Already used in hundreds of websites worldwide: – symfony.com – lockerz.com – exercise.com – Opensky.com
54. REAL WORLD
55. New project comes in •  User account platform •  SSO or webapp can share informations with other accepted webapps •  API for third party websites •  SDK for the API •  Other connected webapps can be done in any php frameworks or languages.
56. Think standards! •  OpenID •  OAuth2 •  CAS
57. Identify the best solution for your needs
58. OAuth2 •  RFC is ~40 pages long. •  OAuth2 is a complicated subject with a lot of HTTP workflows •  Do you really want to start from scratch?
59. Don’t suffer the Not Invented Here syndrom
60. How to choose? •  Search for other libraries in ruby / php / python / whatever •  Is the developper well known? •  Is the company behind renowned? •  Is the library well tested? •  Follow your guts!
61. Porting •  Porting OAuth2 library from ruby was complicated. – RAKE middleware to Symfony2 architecture – I had no knowledge of ruby
63. Porting •  Port the test early! •  markTestIncomplete()
64. How to port? •  Port only what you need – Port only the things you need – Make it works – Repeat. •  Port the whole thing in one time
65. But be pragmatic •  Do not try to immediately release the port as open source •  Make it work for your project, and maybe one day, open source it when you’ll be happy of it
66. OAuth2   Provider   Consumer   (Symfony)   Consumer   (Silex)   Consumer   (ZF)   OAuth2 consumers
67. Think independent •  Do you want to tie your SDK to a Framework? •  SDK is framework-independent library •  Only dependency is Buzz (because it’s great) •  Only after that, integrate it into framework – Silex service provider – Symfony2 bundle – symfony 1.x plugin
68. QUESTIONS? rate this talk http://joind.in/3700
69. THANKS ! Marc Weistroff Sensio Labs marc.weistroff@gmail.com @futurecat http://www.marcw.net